Elevated renal afferent nerve activity in a rat model of endothelin B receptor deficiency

Renal nerves have been an attractive target for interventions aimed at lowering blood pressure; however, the specific roles of renal afferent (sensory) versus efferent sympathetic nerves in mediating hypertension are poorly characterized. A number of studies have suggested that a sympathoexcitatory signal conveyed by renal afferents elicits increases in blood pressure, whereas other studies identified sympathoinhibitory afferent pathways. These sympathoinhibitory pathways have been identified as protective against salt-sensitive increases in blood pressure through endothelin B (ETB) receptor activation. We hypothesized that ETB-deficient (ETB-def) rats, which are devoid of functional ETB receptors except in adrenergic tissues, lack appropriate sympathoinhibition and have lower renal afferent nerve activity following a high-salt diet compared with transgenic controls. We found that isolated renal pelvises from high salt-fed ETB-def animals lack a response to a physiological stimulus, prostaglandin E2, compared with transgenic controls but respond equally to a noxious stimulus, capsaicin. Surprisingly, we observed elevated renal afferent nerve activity in intact ETB-def rats compared with transgenic controls under both normal- and high-salt diets. ETB-def rats have been previously shown to have heightened global sympathetic tone, and we also observed higher total renal sympathetic nerve activity in ETB-def rats compared with transgenic controls under both normal- and high-salt diets. These data indicate that ETB receptors are integral mediators of the sympathoinhibitory renal afferent reflex (renorenal reflex), and, in a genetic rat model of ETB deficiency, the preponderance of sympathoexcitatory renal afferent nerve activity prevails and may contribute to hypertension.NEW & NOTEWORTHY Here, we found that endothelin B receptors are an important contributor to renal afferent nerve responsiveness to a high-salt diet. Rats lacking endothelin B receptors have increased afferent nerve activity that is not responsive to a high-salt diet.

Effects of Self-Efficacy and Locus of Control on Future Preconception Counseling Plans of Adult Women With Type 1 Diabetes

Objective. The American Diabetes Association (ADA) recommends that women with diabetes attend preconception counseling and improve blood glucose levels before pregnancy to decrease risks of adverse outcomes. However, two-thirds of women with diabetes do not plan their pregnancies. Research has examined views regarding preconception counseling of pregnant women with diabetes, but perceptions of women with diabetes who have never been pregnant have not been explored. The purpose of this study was to examine the relationship between women's locus of control, self-efficacy, and outcome expectations of preconception counseling. Design and Methods. A sample of 147 nulligravid women with type 1 diabetes (mean age 25.9 years) was recruited online to complete a self-report survey. Measures included a sociodemographics form, a study-specific questionnaire regarding diabetes management and education, the Reproductive Health Attitudes and Behaviors instrument, and the Diabetes-Specific Locus of Control measure. Results. A standard multiple linear regression analysis indicated that self-efficacy was positively associated with expectations of preconception counseling (P <0.001), whereas self-blame was negatively associated (P = 0.001). Three-fourths of the women reported not receiving preconception counseling from health care providers. Conclusion. Self-efficacy was positively associated with women's expectation of preconception counseling usefulness, whereas self-blame for poor disease management was inversely related. The low reported rates of preconception counseling demonstrate that ADA recommendations for starting preconception counseling at puberty have not been followed uniformly. Women with diabetes should be provided education to increase their belief that they have control over their disease, which may lead to positive perceptions of preconception counseling and healthier pregnancies.